I photographed this Male Lesser Scaup flapping his wings last October on the coast of North Carolina.   I am processing images from last year because all my photography trips are canceled due to the pandemic.  The Lesser Scaup and the Greater Scaup look almost identical, at least in the bird book they look identical.  I spent lots of time trying to identify this duck and finally realized that the Lesser Scaup has a distinctive peak at the back of its crown.  The Lesser Scaup is also much more widespread than the Greater Scaup which should have been a huge clue but I overlooked that fact.  This Male Lesser Scaup treated me by standing up and flapping his wings and giving me time to photograph him.